Screw-cutting die



May 12, 1931. E. T. BYSSHE ETAL 1,804,459

SCREW CUTTING DIE Filed April 5, 1927 2 Sheets-Sheet l May 12, 1931. v T. BYSSHE ET AL 1,304,459

SCREW CUTTING DIE Filed April 5, 1927 2 Sheets-Sheet 2 -mwmz Patented May 12, 1931 UNITED STATES PATENT OFFICE ERNEST T. BYSSHE AND ROBERT R. FINN, OF SPRINGFIELD, VERMONT, ASSIGNORS TO J ONES &; LAMSON MACHINE COMPANY, OF SPRINGFIELD, VERMONT, A CORPORATION OI VERMONT SCREW-CUTTING DIE Application filed. April 5, 1927. Serial No. 181,068.

This invention relates to dies for cutting screw threads, capable of use as stationary or rotating dies, and constructed so that the parts can be adjusted and the chasersremoved without the use of tools of any kind.

It is an object of the invention to provide a die which is strong and compact and n which the locking member which locks the d1e in its closed position is engaged and held at points all around its circumference. It 1s a further object of the invention to provide a die with a floating support to insure proper centering of the die when starting on the work. These and other novel and advantageous features will be apparent to one skilled in the art from the disclosure of the invention in the following description and on the drawings, of which Figure 1 is a front elevation of a stat onary die constituting an embodiment of the invention.

Figure 2 is a rear elevation of the same.

Figure 3 is a side elevation of the same.

Figure 4; is a section on the line 4-4 of Figure 1. a

Figure 5 is a side elevation of a rotatable die embodying the invention.

Figure 6 is a perspective of an ad uSt-mg nut.

Figure 7 is a perspective of a pin for locking the adjusting nut.

Figures 8 and 9 are sections on the line 88 and 9-9 respectively of Figure 4:.

Figure 10 is a perspective of the trip pin for opening the die.

Figure 11 is a section on the line 11-11 of Figure 1.

Figure 12 is a perspective of the locking sleeve.

Figure 13 is a perspective of the locking plate.

Figure 14 is a perspective of the rear retaining rings.

It Wlll be noted that Figures ,4 and 7-11 are drawn to a larger scale than the other figures.

The die comprises a body 20 having a rearwardly extending shank portion 21. The forward end of the body 20 is enlarged and is radially slotted to receive a suitable number of chasers 22, four chasers being illustrated in Figure 1. The chasers are held against lon itudinal motion relative to the body as by keys 23. The body 20 is also preferably recessed to receive springs 24 (Figure 11) which are arranged to bear against pins 25 fixed in a side of the respective chasers 22. These springs exert a moderate pressure radially outward on the chasers so that the chasers when free thus move away from the work. The chasers are moved inwardly toward the work when the die is being closed by the camming action of a locking sleeve 26 which has within its forward end an interior sloping cam face 27 adapted to bear against corresponding cam faces on the ends of the respective chasers. The sleeve 26 is shown in perspective in Figure 12. As will be seen from Figure 4, forward motion of the sleeve 26 will cause the cam surface 27 to ride on the ends of the chasers to force them inwardly to cutting position. In order to close the die therefore, the sleeve 26 must be moved forward. This may be done, in the form of die shown in Figure 5, by pushing against the rear face of the die manually, or bysuitable operating parts of the machine in which it is used. In the form of die shown in Figure 3, the sleeve 26 may be moved forwardly by rotating the sleeve as by a suitable handle 28, a forward motion of the sleeve being therebyefi'ected by a camming action as will hereinafter be described.

It may be noted here that the form of die illustrated in Figure 5 is intended to be mounted for rotation, the shank portion 21 being held in a rotating member of a suitable machine. The form illustrated in Figure 3 is intended to be held fixed as in the turret of a turret lathe, this form of die being provided with a secondary or floating shank 29 which encloses the shank 21 and is held in the turret or other support.

The mechanism for moving the locking sleeve 26' forwardly to close the die and f0: locking the sleeve in its forward position is as follows An adjusting nut 30 (Figure 6) is screwwhen the die is adjusted for size or the chasers are removed. Thus the nut 30 and the body 20 are virtually integral during the operation of the die, and may be thought of together as constituting the body portion of the die. The adjusting nut is of peculiar shapehaving an enlarged rearward portion provided with a series of longitudinal channels 32 around its periphery. These channels receive. a series of teeth 33 of a retaining ring 34 (Figure 14) and a series of teeth 35 of a locking plate 36 (Figure 13). The teeth 33, 35 are fitted to slide in the channels .32 and thus to permit longitudinal motion of the ring 34 and plate 36 with respect to the adjusting nut 30, but to prevent rotation of these members relative to the nut 30 as long as their teeth remain in the channels 32. As shown in Figures 4 and 11, the retaining ring 34 is held against 1ongitudinal motion relative to the sleeve 26 as by a circular spring wire 37 which engages in suitable opposing recesses in the ring and sleeve but permits relative rotation of these parts. The locking plate 36 is held between the sleeve 26 and the retaining ring 34 so that the three members 26, 34 and 36 move together longitudinally but are rotationally independent of one another. In order to cause the sleeve 26 to move longitudinally whenever it is rotated, a pair of cam members 38 are formed on an interior ring-shaped portion or flange 39 inside the sleeve, these cam members being adapted to fit into correspondin inclined slots 40 extending rearwardly IOIIl the forward end of the adjusting nut 30. The nut 30 is normally locked against rotation relative to the body 20 by means thereinafter described. Hence rotation of the sleeve 26, through the camming action of the cam members 38 in the slots 40, causes the sleeve to move longitudinally. Conversely, longitudinal motion impressed on this sleeve 26 results in a rotation thereof relative to the bod 20. In closing the die therefore, it is su cient either to press the sleeve forward by pushing manually against the rear face of the die, or to turn the sleeve as by the handle 28, either action resulting in a forward movement of the sleeve 26 to close the die. Since the locking plate 36 and its retaining ring 34, as previously explained, are constrained to move longitudinally with the sleeve 26, forward motion of the sleeve in closing the die carries forward the plate and ring, these two members being held against rotation, however, by the engagement of their teeth 35, 33 in the channels 32 of the adjusting nut 30. When the die is fully closed, the plate 36 is moved far enough forward for its teeth 35 to clear the forward ends of the channels 32. This releases the locking plate 36 for limited rotation relative to the nut 30. As shown in Figures 4 and 8, such rotation is brought advanced a desired amount.

about as by a suitable spring 41 bearing against a suitable pin 42 set into the plate 36 and to abut a portion of the nut 30. The spring 41 being normally under compression, rotates the locking plate 36 as soon as the teeth of the latter clear the ends of the channels 32, this rotation of the plate 36 being limited to a small are by a pin 43 (Figure 6) set into the nut 30 in a position to engage the teeth 35 of the plate 36 when the latter has turned through a small are. As shown in Figure 8, this slight rotation of the locking plate 36 causes each of the teeth 35 to overlap a portion of the forward face of the enlarged part of the nut 30 and thus to lock the plate 36, by engagement with the nut 30 at points all around its circumference, against rearward longitudinal movement. This also locks the sleeve 26 against rearward movement and thus locks the die in its closed position,

In order to unlock the die to permit it to open, a suitable trip pin 44 (Figure 10) may be provided. This pin is arranged to move in a radial direction in a recess 440 formed in the sleeve 26 and has a notch with a cam face 45 adapted to engage a suitable projection or pin 46 in the forward face of the locking ring 36. A flat rear face 442 is provided on the pin 44 to bear against the ring 36 to maintain the cam face 45 in position to engage the pin 46. The pin 44 is normally held outward as by a light spring 47. When, however, the pin is pushed inwardly (Figure 9), the cam face 45 acts on the pin 46 to rotate the locking ring 36 back to the position in which the teeth 35 are aligned with the channels 32 of the nut 30, this rotation of the ring 36 being against the pressure of the spring 41. A suitable recess 441 is provided in the flange 39 to receive the pin 46 and permit its motion with the ring 36. \Vhen the teeth 35 are aligned with the channels 32 leaving the ring 36 free to move rearwardly with respect to the nut 30, such rearward movement is caused by a series of springs 48 (Figure 11) which are set into suitable recesses in the enlarged portion of the body 20 and which constantly press the sleeve 26 and its associated members in a rearward direction. Thus by pressing the pin 44, the plate 36 is unlocked, the springs 48 move the plate 36 with the ring 34 and the sleeve 26 rearwardly so that the springs 24 are permitted to move the chasers 22 radially outward, and the die is thus opened. In the form of the die illustrated in Figure 5, which is designed to be rotated, the pin 44 may be depressed by being made to come in contact with a suitably positioned stationary member on the machine adapted to engage the pin when the die has In the stationary form of the die illustrated in Figures 3 and 4, a suitable cam member 49 may be adjustably mounted on a suitable spindle carried by'a guide plate 51 mounted on' an enlarged forward end portion of the secondary shank 29. In order to hold the die against rotation relative to the secondary shank, a )air ofguide pins 52 are fixed in the rear iace of the retaining ring 34 and extend into suitable perforations 53 through the guide plate'51. Through these guide pins 52 and the plate 51, the torque of .the cut is taken. The plate 51 is threaded or otherwise mountedfor rotation on the secondary shank 29. a set screw 54 or other equivalent means being provided to lock the plate and shank against relative rotation during the operation of the die. As shown, the set screw 54 is provided with a knurled head. In order to adjust the die for size or to remove the chasers, as will be hereinafter described. it is necessary to loosen the set screw 54 since the plate 51 must by reason of the guide pins 52 rotate with the retaining ring 34 and the nut 30 and the latter must be rotated when the die is adjusted or the chasers removed. The shank 21 of the die is made small enough to have a certain amount of play inside the secondary shank 29 and is supported therein as by a pair of cone washers 55, 56. The cone washer 55 engages a frusto-conical shoulder 57 of the body 20 while the cone washer 56 engages a frusto-conical face on the head of a screw member 58 which is threaded into the interior of the shank 21 and is thereby adjustable lon gitudinally thereto. A light spring 59 is provided to bear against the washer 5 5 to press it forwardly into engagement with the shoulder 57 of the body 20, A heavier spring 60 is provided within the rear end of the shank 29, this spring being of sufficient strength to move the whole die rearwardly when released from the work. The two springs 59 and 60 maintain the cone washers 55, 56 normally against the incl ned faces respectively opposed thereto and thushold the die properly centered when it starts on the work. 1

Means are provided also for adjusting the diameter of the cuts on the work. This adjustment is accomplished by regulating the longitudinal position which the sleeve 26 occupies when the die is closed. This ad ustment may be made when the die 1s either closed or open. .Since the position of the sleeve 26 relative to the adjusting nut 30 when the die is closed is definite and not changeable in the mechanism illustrated, such diameter adjustment is made by moving the adjusting nut 30 longitudinally on the body 20. This movement of the nut 30 carries with itthe sleeve 26, the locking. plate 36 and the retaining ring 34. In order to lock the'adjusting nut 30 in adjustablefixed relation to the body 20, the nut 30 is provided with an arcuate rack 61 (Figure 6), the teeth of which are normally engaged by a serrated surface 62 on a sliding in 63 (Figures 7 and 11) which is carried y the body 20. A suitable spring 64 located within a recess in the rear end of the pin 63 normally engages the interior flange 39 of the sleeve 26 and presses the pin 63 forward. The teeth 62 of the pin 63, when the latter is in its forward position, engage some portion of the rack 61 and thus lock the nut 30 against movement relative to the body 20. When,

however, the pin 63 is pushed rearwardly, the teeth 62 slide clear of the rack 61 and ride over an annular depression 65 which permits the nut 30 to be turned, and by means of its threaded engagement with the body 20 to move forwardly or rearwardly with'respect thereto. U on release of the pin 63, it is moved forwar ly by the spring 64 bringing the teeth 62 in mesh with the rack 61 and locking the nut 30 again. Thus the adjustmentof the dieis made manually without the use of tools of any description. In order to indicate the amount of adjustment, a suitable scale 66 may be marked on the sleeve 26 adjacent its forward end, this scale reading against a suitable index line 67 on the body 20, as shown in Figure 3. A suitable. recess 390 is provided in the forward face of the flange 39 to receive the rear end of the pin 63 and to permit the rotation of the sleeve to open and close the die and for removalof the chasers.

In order to permit the removal of the chasers from the die, the forward end of the sleeve 26 is provided with recesses 68 (Figure 1). By rotatingthe sleeve 26 sufliciently, the recesses 68 may be brought to register with their respective chasers 22 whereupon the chasers may be slid radially. outward through the recesses. These recesses are so arranged as not to re ister simultaneously with the chasers, so t at in removingthe chasers from the die, the recesses 68 register therewith serially, thus permitting the chasers to be removed one at a time. Since the normal rotation of the sleeve26 in opening the die is limited. by the rearward ends of the slots 40, further rotation of the sleeve to remove the chasers requires the-rotation of.

the nut 30 with the sleeve. Hence-to remove the chasers after opening the die, the operator must loosen the set screw 54, 'push'the pin 63 rearwardly to release the nut 30, and

. engaging the frusto-conical faces of said die,

and means for ressing said mutually engaging faces toget er.

2. In combination, a screw-cutting die having oppositely inclined shouldered portions, a supporting member, and means providing a floating connection between said die and support and acting to hold the die centered yieldingly to permit the die to conform to irregularities of alinement of the work, said means comprising elements with inclined faces engaging said shouldered portions of the die and resilient means normally pressing said engaging faces against said shouldered portions.

3. In combination, a screw-cutting die having opposing frusto-conical shouldered portions, a supporting member, and means providing a floating connection between said die and support, said means comprising a pair of cone washers normally in coniact with said shouldered portions, and resilient means normally pressing said washers against said portions.

4. In combination, a screw-cutting die having die-opening mechanism normally locked when the die is closed, a supporting member permitting said die limited longitudinal movement relative thereto, a floating connection between said die and support, means for preventing relative rotation between said die and support, means for resiliently pressing said die rearwardly with respect to said support, and means carried by said support for unlocking said die-opening means upon movement of said die to its forward'limit.

5. In a screw-cutting die, a body member, radially slidable chasers carried by said body having sloping cam faces on their outer ends, means for moving the chasers inwardly comprising a cam member movable forwardl for camming engagement with said cam aces, means for moving said cam member forwardly, and means for locking said cam member in its forward position, said locking means comprising an annular plate having spaced portions arranged around its entireperiphery for locking engagement.

6. In a screw-cutting die, a body portion, radially slidable chasers carried by said portion having cam faces on their outer ends, means for moving said chasers inwardly comprisin a cam member mounted for limited camming movement on said cam faces whereby the chasers are moved inwardly to closed position, means for moving said cam memer, and means for locking said cam member tion, the other of which engages the in its limiting ition of camming engagement with sai chasers, said locking means comprising an annular member having end faces, one of which engages said cam member when the annular member is in locking posiody portion of the die, said locking member having locking engagements with both the cam member andbody portion distributed around its entire periphery.

In a screw-cuttin die, a body member comprising a substantiall cylindrical por- 1 tion and an enlarged portion at the forward end thereof, chasers radially slidable in said enlarged portion, said chasers each having a sloping cam surface on the outer end thereof, means for moving said chasers inwardly comprising a sleeve surroundin said enlar ed portion having a cam face adjacent the orward end thereof for camming engagement with said chasers to move the chasers inwardly to closed position, 'said sleeve also having an inwardly extending flan e, an adjustment member adjustably fixe on said cylindrical portion of the body, locking means for holding said sleeve in position to hold the chasers in closed position, said locking means comprising a ring en agin the rear face of said inwardly exten ing ange and movable to enga e the forward face of said adjustment mem er on areas distributed around the entire periphery of the lockingmember, and means acting to move the looking member to locking position when said sleeve reaches the limit of its camming movement.

8. In a screw-cutting die, a body member having a forwardface with symmetricall arranged radial slots therein, a chaser radia ly movable in each slot, springs associated with said chasers and arran ed to press said chasers radially outward, an a sleeve on said body having a cam face movable to engage the outer ends of said chasers and to move the chasers radially inward, said sleeve having notches in its forward edge normally out of registry with said chasers and unsymmetrically arranged relative to the chasers so as to be brought into registry with the chasers serially.

9. In a screw-cutting die, a body ortion, a plurality of chasers having cam aces carried by said body, an adjusting nut threaded on said body, said nut having a longitudinally channeled portion and a reduced portion, a sleeve having a portion engageable with the cam faces of the chasers to move the chasers inwardly to closed position when the sleeve moves forwardly, coacting means carried by the sleeve and nut for moving the sleeve axially upon rotation thereof relative to the nut, a retaining ring having an inward toothed flange slidable on said channeled portation of the ring and nut, a locking ring on said nut between said sleeve and retaining ring, said locking ring having an inward flange with teeth fitting in said channels, means for preventing relative longitudinal movement of the sleeve, retaining ring and locking ring, means for rotating said locking ring through a small are when the teeth thereof are moved forward to clear the channels of the nut to move said teeth out of registry with said channels, and means actuable to rotate the locking ring to make the teeth register with said channels.

10. In a screw-cuttingdie, a body member, an adjustment member having a portion in threaded engagement with said body member, thread-cutting chasers radially slidable in said body member, cam means movable forwardly to force said chasers inwardly to closed position comprising a sleeve mounted on said body member and rotatable sufliciently to permit removal of the chasers from the die, means limiting the rotation and axial movement of said sleeve relative to said adjust-ment member, means for normally look ing the adjustment member to the body member, said locking means being manually actuable to release the adjustment member for movement with the sleeve to permit adjustment and the removal of the chasers from the die.

11. In a screw-cutting die, a body member, chasers carried by said body member, an adjustment member screw-threaded on said body member, means normally locking said adjustment member against motion relati've to said body member, and die-closing mechanism comprising a cam member mounted for limited screw motion movement relative to said adjustment member to open and close the die, said cam member having a portion in engagement with said chasers throughout its limited die-opening and closing movement, said cam member also having recesses registerable serially with respective chasers to permit the removal of said chasers from the die when the cam member is turned beyond its limit of die-opening movement, said locking means for the adjustment member being releasable to permit the cam member to turnwith the adjustment member beyond its normal die-opening limit of motion to bring its recesses into registry with the respective chasers and permit the removal of the chasers from the die.

12. In a screw-cutting die, a bod member, chasers slidably mounted in said body member for radial movement, said chasers having cam faces on their outer ends, an adjustment member threaded on said body member and normally locked against motion relative thereto,acammemberlooselymounted on said body member, means permlttin said cam member a limited screw motion 're ative to said adjustment member, said cam member having a cam surface arranged to engage the chasers and close the die in its forward motion, the extent of closing of the die being determined by the forward limit of motion of said cam member, said cam member also having recesses therein arranged to be out of registry with said chasers throughout the normal motion of said cam member but to register serially with respective chasers when said cam member is rotated beyond its normal die-opening limit of motion, and

means for locking said adjustment member, said locking means being manually releasable to permit screw motion of the adjustment member on the body member to adjust the forward limit of motion of the cam member and to permit rotation of the cam member beyond its normal die-opening limit of motion to bring said recesses into registry with said chasers and to permit the removal of the chasers from the die.

13. In a screw cutting die, a body member, a plurality of chasers carried by said body member and movable into and out of cutting position, means for moving said chasers into cutting position, said means including an element movable along the axis of the 'die and operatively associated with into cutting position, said means including an element movable along the axis of the die and operatively associated with said chasers to move the chasers into cutting position by its forward motion and to release the chasers by its rearward motion, and means for lockin said element in its forward position, sai locking means including a lurality of simultaneously releasable a utments independently and rigidly supporting said element against rearward movement at a series of points angularlyspaced about said die.

In testimony whereof we have afiixed our signatures.

ERNEST T. BYSSHE. ROBERT R. FINN. 

